RF640 CMYK COLOUR AND YELLOW CARTRIDGE PROBLEMS

Hie, I have roland rf640 it was running ok the past months but this week i have noticed colour mismatch

eg. darkblue coming cyan or lighter and red printing orange so as the rest of the colours.

I have tried cleaning normal several times and medium cleaning and also manual cleaning but its not improving and the other problem is yellow cartridge #2 when i installed the ink it kept on demanding as it couldnt recognise the cartridge and after time it started printing but when i check ink remaining the slot # for yellow its empty...nothing there. please help!!